Genoa Local Schools Elementary Principal Brenda Murphy said the school has worked hard to provide intervention instruction in reading. She said the district is pleased 97.6 percent met the reading benchmark to advance to the fourth grade.

"We had plans for kids not on track. We had money to hire intervention specialists and use Sylvan Learning from our Title I money," she said. "We used technology to get kids involved in reading."

The Third Grade Reading Guarantee became law in June 2013. It requires students in third grade to hit certain benchmarks on reading tests to be eligible to advance to fourth grade.

The 2013-14 school year was the first year the law was fully in effect. In the 2012-13 school year, roughly 88 percent of students achieved the necessary reading scores for advancement.

"We still have work to do, but we can see that the guarantee has been effective," Richard Ross, state superintendent of public instruction, said in a statement. "While these are great results, we need to continue to focus on the approximately 5,000 boys and girls who didn't meet the threshold last year."

While a score of 400 is considered proficient on the Ohio Academic Assessment, a student needed to score 392 to meet the law's requirements last school year. This school year, students must score a 394 to avoid retention. This also is a year of transition for testing as Ohio switches to Common Core-based standardized tests.

John Charlton, spokesman for the Ohio Department of Education, said third-grade students took the old assessment in the fall. Students who don't reach the 394 mark will take the old assessment again in the spring. The students who do reach that mark will take the new tests in the spring and the future proficiency scores will be based on the results from the new tests.

Many of the students who did not meet the threshold were in the state's larger urban districts. Columbus City Schools had 431 third-graders not hit the benchmark — 12.4 percent of its class — and Cleveland Municipal City Schools had 386 third graders miss the mark — 14.6 percent of its class.

There were 267 districts that didn't have to retain a single third-grader last school year because of the reading law. Another 254 districts had to retain five of fewer third-graders because of the guarantee. More than 1,100 of the third-graders who did not meet the threshold were from Ohio's charter schools, which had a higher percentage of kids fail to hit the benchmark than traditional schools.